1. Field of the Invention
Synthetic organic chemistry is an essential adjunct in a wide variety of industrial fields. Synthesis is important to the preparation of drugs, monomers, additives for fuels, oils, plastics, and the like. In the field of drugs or other physiologically active compounds, it is frequently important to be able to make one of two stereoisomers. To prepare compounds it is usually necessary to functionalize a compound which is commercially available and is of substantially simpler structure than the final product. The oil and coal industries provide a large variety of olefins, which are hydrocarbons or mono-heterofunctionalized.
It is therefore of substantial economic interest to be able to functionalize, that is, enhance the value of various simple compounds, so that they can be used as intermediates in the preparation of more valuable compounds. Epoxides and halohydrins, the latter being useful as intermediates to epoxides, can be used in a wide variety of reactions to produce products of commercial importance.
2. Description of the Prior Art
Methods of asymmetric synthesis may be found in J. D. Morrison and H. S. Mosher, "Asymmetric Organic Reactions," Prentice-Hall, Englewood Cliffs, N.J., 1971, 258-262; S. Yamada et al., J. Am. Chem. Soc., (1977) 99:1988; R. C. Michaelson et al., ibid., (1977) 99:1990; H. B. Kagan et al., Angew. Chem. Int. Ed. Eng., (1979) 18:45; K. Tani et al., Tetrahedron Lett., (1979) 3017; and H. Wynberg and B. Marsman, J. Org. Chem., (1980) 45:158; and K. B. Sharpless and T. R. Verhoeven, Aldrichimica Acta., (1979) 12:63. Tani et al., Tetrahedron Lett. (1979) 32:3017-3020 describe the use of molybdenum catalysts to asymmetrically epoxidize olefinic hydrocarbons in the presence of chiral diols. Katsuki and Sharpless, J. Am. Chem. Soc., (1980) 102:5974-5976 report asymmetric epoxidation employing a combination of titanium alkoxide and tartrates. See also Mimoun, J. Mol. Catal., (1980) 7:1-29; Sharpless et al., Pure and Applied Chem., (1983) 55:589-604; and Sharpless et al., ibid., (1983) 55:1823-1836. Propylene oxide is opened non-selectively with TiCl.sub.2 (OEt).sub.2. Choukroun, Inorg. Chem. Acta. (1981) 58:121-2.